We propose to organize the "Fourth Conference on DNA Topoisomerases in Therapy" at the NYUMC, in October 17-19, 1992. The conference will discuss not only anticancer agents and their target DNA topoisomerase I or II, but also a closely related enzyme DNA gyrase targeted by quinolones and related drugs. There is a host of problems such as enzyme genetics, biochemistry, mechanism of action and resistance, which are common to these two fields of research either developing anticancer treatment or agents effective against infection. The preparation and organization of the conference will include: 1} Dissemination of information, regarding the conference, by mail and by advertisement or announcements in scientific journals. 2} Organization of the conference which will be held as a three-and-half day meeting, with nine plenary sessions of slide presentations, and with two to three poster sessions. Each slide session will include invited speakers, most of them leading experts in the field, and presenters of selected proffered papers There are three major topics to be covered in plenary sessions: (i) Basic research of prokaryotic and eukaryotic topoisomerases, overview and new advances. (ii) Quinolones and related compounds, inhibitors of DNA gyrase, in therapy of infection. (iii) New anticancer agents, inhibitors of DNA topoisomerase I and II, in laboratory, advanced pre-clinical and clinical research. 3} Publication of conference lectures as full-size articles. An attempt will be made to publish selected topics as a volume focussed on camptothecins, a novel class of anticancer drugs.